1. Field of the Invention
The present invention relates to an acoustic wave processing device, a signal processing method, and a non-transitory computer readable recording medium storing a program which transmit and receive an acoustic beam to capture an image of an object to be inspected, such as an organ in a living body, and generate an acoustic image or the like for inspection and diagnosis of the object to be inspected.
2. Description of the Related Art
Hitherto, an acoustic diagnostic apparatus, such as an ultrasound image diagnostic apparatus, which generates an ultrasound image for inspection or diagnosis of an object to be inspected using an acoustic wave, such as an ultrasonic wave has come into practical use in a medical field.
In general, this kind of ultrasound diagnostic apparatus has an ultrasound probe (hereinafter, referred to as a probe) embedded with a plurality of elements (ultrasound transducers), and an apparatus body connected to the probe. In the ultrasound diagnostic apparatus, an ultrasound beam is transmitted from a plurality of elements of the probe toward a subject (object to be inspected) so as to form a predetermined focal point (transmission foal point), an ultrasonic echo from the subject is received by the probe, and the reception signal of the received ultrasonic echo is electrically processed by the apparatus body to generate an ultrasound image.
In the ultrasound diagnostic apparatus, scanning of ultrasonic waves is performed to generate ultrasound images, and the generated ultrasound images are sequentially displayed on a display unit in real time; however, there is a requirement to observe the ultrasound image again for diagnosis after such inspection. For this reason, in the ultrasound diagnostic apparatus, the generated ultrasound images are stored, and in a case where a cine-reproduction mode is selected, the stored ultrasound images are reproduced.
Received wave signal data (element data) is stored, and in the cine-reproduction mode, image data is generated again from the stored element data (JP1993-161641A (JP-H05-161641A). If the conditions for creating an image in the cine-reproduction mode are changed, it is thereby possible to change the image quality of the ultrasound image in the cine-reproduction mode to be different from the ultrasound image generated in real time, and for example, to obtain a higher-image quality ultrasound image.
The ultrasound beam drives a plurality of elements based on a predetermined transmission delay pattern and is transmitted so as to form the set focal point. This ultrasound beam has a shape having a width in a transverse direction. For this reason, there is a problem in that information of a reflection point at a position shifted in a transverse direction is picked up, and is reproduced on the ultrasound image as a so-called ghost signal.
In regard to this problem, in the ultrasound diagnostic apparatus, so-called multiline processing in which a plurality of pieces of data (element data or reception data) obtained by each transmission are superimposed according to the reception time or the position of the element to correct data in the generation of one ultrasound image (JP2009-536853A). In a case of ghost signals, even if the pieces of data are superimposed according to the reception time or the position of the element, ghost signals are superimposed in a shifted state and cancel each other; thus, it is possible to remove the ghost signals.